There may be a lot of unsettled foreclosures, and a lot of homeowners under water, but one key group keeps feeling better and better about the housing market. Home builders. The NAHB/Wells Fargo Housing Market Index has reached its highest level in four years. The index is now at 29, up from 25 in January. That's the fifth consecutive month home builder confidence has risen, according to the National Association of Home Builders . From the NAHB release: “Builder confidence has doubled since September as measured by the HMI,” said NAHB Chairman Barry Rutenberg, a home builder from Gainesville, Fla. “Given the recent improvements in new home starts and the increasing number of markets included in the NAHB/First American Improving Markets Index, this consistency suggests that the housing market is moving toward more sustainable growth.” Rutenberg cautioned that the housing sector remains very fragile with significant differences between individual markets, and said policymakers must guard against actions that could impede or even reverse the gains of recent months. “This is the longest period of sustained improvement we have seen in the HMI since 2007, which is encouraging,” said NAHB Chief Economist David Crowe. “However, it is important to remember that the HMI is still very low, and several factors continue to constrain the market. Foreclosures are still competing with new home sales, and many builders are seeing appraisals come in at less than the cost of construction. Additionally, prospective home buyers are finding it difficult to qualify for a mortgage.” Read the full release here .